shreya_2003
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The wording is quite confusing would i start with x~b(20,0.45)
And then find X /> 12? and then square it by 2 ?

So (X/>12)= 1- (X</11) = 0.1308
and then square it giving 0.01710?
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UrFellowMedic
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(Original post by shreya_2003)
The wording is quite confusing would i start with x~b(20,0.45)
And then find X /> 12? and then square it by 2 ?

So (X/>12)= 1- (X</11) = 0.1308
and then square it giving 0.01710?
Firstly use the binomial to find the probability of at least 12 winning cards. Now that’s the probability that one store has at least 12. You said square it, don’t you think that’s the probability of exactly 2 stores having it? You might need to set up a distribution again, that’s my hint I’ll give you,
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shreya_2003
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(Original post by UrFellowMedic)
Firstly use the binomial to find the probability of at least 12 winning cards. Now that’s the probability that one store has at least 12. You said square it, don’t you think that’s the probability of exactly 2 stores having it? You might need to set up a distribution again, that’s my hint I’ll give you,
Im still a bit lost. So would the distribution be (12,0.45)
and then be (X≥2) ?
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UrFellowMedic
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(Original post by shreya_2003)
Im still a bit lost. So would the distribution be (12,0.45)
and then be (X≥2) ?
Not quite. You found the probability that ONE store has AT LEAST 12 winning cards (0.1308). Now you need to find the probability that AT LEAST 2 stores have these 12 winning cards. So you are correct with P(S >/ 2 ) (I used a different letter here since you already used X to find the 0.1308 probability), but wrong distribution numbers. Look, you got 8 stores in your sample, you got the probability (0.1308), and it wants you to find at least 2 having this probability.
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shreya_2003
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(Original post by UrFellowMedic)
Not quite. You found the probability that ONE store has AT LEAST 12 winning cards (0.1308). Now you need to find the probability that AT LEAST 2 stores have these 12 winning cards. So you are correct with P(S >/ 2 ) (I used a different letter here since you already used X to find the 0.1308 probability), but wrong distribution numbers. Look, you got 8 stores in your sample, you got the probability (0.1308), and it wants you to find at least 2 having this probability.
So (8,0.1308) for the second part?
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UrFellowMedic
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(Original post by shreya_2003)
So (8,0.1308) for the second part?
Precisely yep.
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shreya_2003
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(Original post by UrFellowMedic)
Precisely yep.
8 right? bc i just edited to 8 the minute u replied to me.
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UrFellowMedic
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(Original post by shreya_2003)
8 right? bc i just edited to 8 the minute u replied to me.
Yes because you have a sample of 8
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shreya_2003
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(Original post by UrFellowMedic)
Yes because you have a sample of 8
thank you for the help!
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